Presser-foot-lifting mechanism for sewing-machines.



P. A. HERR.

PRESSER FOOT LIFTING MECHANISM FOR SEWING MACHlNES. APPLICATIONflLED JUNE 23, 19M.

1,241,733. Patented Oct. 2, 1917.

WI T/V E 885 8:

INVENTOR fir 4 1: 4. WM AZ 4 w? UTED STATES PATENT OFFICE.

PARK .A. HERE,

0]? SAYBROOK, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFAC- TURING COMPANY, A CORPORATION OF NEW JERSEY.

Specification of Letters Patent.

Patented Oct. 2, 1917.

Application filed June 23, 1914. Serial No. 846,726. a ,i

To all whom it may concern:

Beit known that I, PARK A. I'IERR, a citizen of the United States, residing at Say brook, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Presser-Foot-Lifting Mechanisms for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to presser-foot lifting mechanisms for sewing machines, being especially adapted for use in connection with machines for sewing heavy work, such as harness, belting and the like, in which the work is fed by lateral movements of the needle.

The present improvements comprise means whereby the presser-foot may be automatically lifted above the work immediately prior to and during each effective movement of the sewing machine feeding mechanism, the presser-foot being intermittently lifted a uniform distance above the work, regardless of varying thicknesses thereof.

The presser-bar clamping and lifting elements consist of a collar loosely fitted upon the endwise-movable presser-bar of the machine and having a laterally-projecting split portion, each section of the said split portion being a thickened Wall merging into the relatively-thin main curved wall of the collar. The collar is embraced by the yoke of a clamping-lever, each arm of the yoke being fulcrumed upon the base of the collar on a line lengthwise of, and intersecting, one of the thickened walls of the split portion; and a contact-stud at the rear of the yoke abuts the opposite and spaced wall of the split portion. When the lever is lifted, a clamping force is applied to the split portion of the collar inopposite directions, and the sections thereofare forced toward each other; with the result that the entire inner curved area of the collar is compressed about the presser-bar. The succeeding lift of the lever elevates both the collar and the presser-bar clamped thereby.

The lifting means for the clamping-lever comprises a lifting-lever pivotally mounted atone end upon the overhanging arm of the machine, and intermittently pressed upward by an endwise movable post actuated by a rotary cam-disk on the driving shaft of the machine.

In a. modified form of the improvc ments, one arm of the clamping-lever yoke is formed as a bell-crank and is adapted to act upon one section of the split portion of the collar through the intermediary of a link having a bent-end which supports the contact-stud. Each form of the improvements is such that the collar is compressed upon the presser-bar by a force which decreases its normal diameter, the force being applied at opposite sides of the enlarged split portion of the collar and in a plane exterior the periphery of the bar. By the aforesald arrangement, the twist or torsion imposed upon the presser-bar of a sewing machine by known devices of the present char acter is largely reduced,and therefore the bar is not bent under the repeated action of the lifting-mechanism.

In the drawings, Figure 1 is a perspective view of the improvements as applied to a sewing machine. Fig. 2 is a top plan view of the clamping-collar and the parts immediately connected therewith. Fig. 3 is a perspective view of the modified form of the clamping-collar, in which a link is dis posed intermediate one yoke arm of the lifting-lever and a lug projecting from one section of the split portion of the collar; and Fig. 4 is a similar view from the rear of the clamping-collar. Fig. 5 is a perspective view of the collar detached from its clamping elements.

In Fig. 1 of the drawings is illustrated, by dotted lines, part of the overhanging arm A of a sewing machine, in the head of which is journaled the usual endwise-movable presser-bar 1, supporting the adjustable presser-foot 2. A shaft 3, journaled in the overhanging arm, is provided with a rotary cam-disk l: which is employed to exert a lifting pressure upon the presser-bar through the intermediaries hereinafter dcseribed.

In practice, the presser-bar is springpressed downwardly into engagement with the work resting upon the work-plate of the machine, and is elevated above the work during the work feeding action. To this end, a clamping-collar 5 is loosely fitted upon that portion of the presser-bar which projects above the overhanging arm A. The collar is formed with a lateral projection, which is split to form two sections a, I), having thickened walls which merge into i the relatively-thin main curved wall of the collar. The increased thickness, and hence weight, of the: separated sections or endportions a, b, of the split collar facilitates compression of the same against the springaction of the connecting circular wall, as will be understood without further expla nation.

The collar 5 is embraced by the-yoke of a clamping-lever 7 the arms of the yoke being fulcrumed by. means of stud-screws 8, upon thev enlarged base 5 on a line extending lengthwiseof, and intersecting, the

section b. At the rearof its yoke, the olamp' ing-lever is orovided with an upwardly extending lug 7 apertured to receive the contact-screw 9., which abuts section a. It will be seen that upward movement of the clamping-lever will apply a compressive force on opposite sides of the split portion of the collar, the sections a and Z) being moved toward-each other, with the result that a circumferential tensile stress is imposed upon the collar and the entire inner curved area thereof is compressed about the presser-bar. The split. collar 5 may also be considered as a flexible strap substantially surrounding the Presser-bar 1 and having two relatively movable end-portions a, b,disposed at one side of the pressersbar 1. The clampinglever 7 acts to force the end portions of the strap 5 toward each other thus causing said strap to grip the bar with substantial uniformity circumferentially thereof. I

The lifting device for the clamping-lever consists of a lifting lever-10 fulcrumed at one end by means 'of'stud-screw 11 upon the overhanging arm A of the machine, and at its opposite end provided with opposed upwardly extending guide-walls 12 forming a U-.shaped seat for the end of the clamping lever. Intermediate itsuends, the lifting lever rests within a transversechannel 13 formed in the upper end of a post 1 3 end-- wise movable within a suitable bearinw provided in the overhanging arm A. At its lower end the post 13 is provided with a roller-stud 1A adapted to be engaged by the periphery of the raised cam surface 15 of rotary cam-disk 4. The-cam imparts an intermittent movement to the "lifting lever. In one stage 'of its movement, the liftinglever turns the clamping-lever 7 upon its fulcrum-studs to clamp the collar 5 upon the presser-banand in a second stage of its movement the lifting lever elevates the presser-bar to maintain the presser-foot above the work during the advanceof the work feeding element of the machine. Immediately after the feeding movement has been imparted to the work, the post rides off the camsurface of the disk 4 and the presser-bar clamping elements are released. A spring. 16, having one end secured upon the'overhanging arm A and its opposite end of the clamping-lever yoke is formed as a bell-crank and is connected, by means of pivotalsstud 19, with one end of a link 20.

The opposite bent-endof link 20 is provided with a contact-screw 21 which abuts-the face of a lug .22 projecting from section .a of the split portion of collar 5. In its action, the modified form of the clamping-lever is similar to the form illustrated in Figs,.1 and of the drawings, its leverage, however, being increased by the use of the link 20.

, It will be understood that any suitable lifting means may be employed for the clamping-lever, and that various modifications, in addition to those herein shown and described, may be made, within the. scope of the invention. A

Havingthus set forth the nature of the invention, what I-claimherein is H- I 1. In presser-foot lifting ,mechanism for sewing machines, the combination witha presser-bar, of a collar loosely fitted upon said presser-bar, said collar being split at one point circumferentially thereof,.;therehy defining two relatively movable portions, and being continuous ,at all other points circumferentially thereof, whereby it may. re; sista circumferentialtensile stress, means acting on said portions of the collar to force them toward each other, thereby causing said collar to grip the bar, said means 'acting subsequently to lift the .bar.

2.. In presser-foot lifting mechanismifor sewing machines, the combination With a presser-bar, .of :a split collar loosely fitted upon, said presser-bar, means acting upon the portions of said collar adjacent said split withla force directed in a plane-spaced from said I presser-bar to draw said collar tightly, about said pressersbar, :said means acting subsequently to lift the bar.

3. In presser foot lifting mechanism for sewing machines, the combination with a presser-bar, of a vertically movable split collar loosely fitted upon the presser-bar, lift; ing means adapted to. decrease the normal diameter of said collar,asaid.lifting .means acting upon the collar with a force directed in a plane spaced from the presser-bar.

- 4. In'presser-foot mechanism, for sewing machines, .the combination with .a; vertically movable collar adapted to .be loosely .fitted upon .the resser-bar of a sewing machine and formed with a laterally. extending split portion affording eireumfenentially spaced sections, of a. :clamping lever'fuls crumed upon one section of said split portion of the collar and having a member adapted to apply a force to the opposite 13o section thereof directed toward the first mentioned section in a plane spaced from the axis of the presser-bar, whereby said collar is caused to securely grip the presserbar.

5. In presser-foot lifting mechanism for sewing machines, the combination with a presser-bar, of a split collar in the form of a flexible strap substantially surrounding said presser-bar and having two relatively movable end-portions disposed at one side of the presser-bar, means for forcing the end-portions of said strap toward each other, thereby tightening said strap about the presser-bar, said means acting subsequently to lift the bar.

6. In presser-foot lifting mechanism, the combination with a collar adapted to be loosely fitted upon the presser-bar of a sewing machine and formed with a laterally extending split portion affording spaced sections, of a clamping-lever formed with a yoke embracing said collar, means for pivotally connecting the arms of said yoke to the collar on a line extending lengthwise of one of said spaced sections, and a contact member carried by the lever and adapted to engage the opposite spaced section.

7. In presser-foot lifting mechanism, the combination with a collar adapted to be loosely fitted upon the presser-bar of the sewing machine and formed with a laterally extending split portion affording spaced sections, of a lever fulcrumed upon one of said spaced sections, and a link connected with said lever and provided with a contact member adapted to engage the opposite spaced section.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

PARK A. HERE. Witnesses W. Lee I-IELMs, II. A. KoimnMANN, Jr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

